# Screen turns black, unresponsive when calling

When I make calls the screen turns black so I cannot access the UI for using the keypad and speaker, or end the call. If I press the wake button on the side of the phone, the screen turns on for maybe a quarter of a second and goes off again.

Even more frustrating, if the phoned is locked and I receive a call, the screen remains black so that I cannot answer the call. Pressing the wake button makes my ringtone stop. It isn't quite clear what happens then but I can't hear anything so I presume that the call is being declined. After this I need to reboot the phone to make it useable.

I think, but I'm not entirely certain, that this behaviour started when I upgraded to Taalojarvi.

How can I diagnose or fix the issue?

I've just tried this with the alarm function, and when the phone is locked, the screen doesn't turn on when the alarm goes off. To me, this indicates that the problem is with waking up, rather than with the phone call application.

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In addition to what has been said by @spiiroin, for diagnosis try the CSD tool. You can open it by dialling *#*#310#*#*. Choose Proximity sensor and follow the instructions.

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Thanks for this. My proximity sensor is failing this test.

( 2016-05-23 21:47:20 +0300 )edit

Your phone shows symptoms of proximity sensor locked to "covered" state:

• When there is an incomin call / alarm - display turns on as soon as the proximity sensor is not covered -> if the sensor is stuck to covered state, display stays off (and power key is reserved in this state for silencing the call / snoozing the alarm).
• When there is ongoing call, display is turned off whenever the proximity sensor is covered -> power key will unblank the screen, but then in call proximity blanking causes it to be turned off again.

Sweat, grease or dust on the display easily makes the sensor report it is covered all the time -> wiping the sensor area (the corner of the display next to the power button) should help with that.

If there are dust particles underneath the glass, gently tapping the phone against palm might help.

In any case you can use triple power key press (3 presses within one second) to trigger temporary proximity sensor override (the sensor is considered to be in not-covered state until it starts reporting state changes again). The detection for the triple press is done separately from more normal power key activity, so any ringing alarms will be snoozed and calls silenced. But otherwise you should be able use the phone ui normally and for example answer the silenced call.

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There's a crack in my screen so a little dust has built up underneath the glass, and this seems to be making the sensor fail. The triple tap trick is useful; I didn't know about that.

( 2016-05-23 21:48:58 +0300 )edit

This appears to be the same bug as reported here:

https://together.jolla.com/question/193485/any-workaround-for-malfunctioning-proximity-sensor-xa2

The above report has more votes, and probably more relevant information. This report (135055) should probably have the 'proximity sensor' tag applied to it, as currently (2019-01-17) it does not.

Note that in my case, using an Xperia XA2 phone, the CSD tool test needs to be done fairly soon after the phone has been freshly rebooted. After it has been up and running for a period, the proximity sensor status, as seen by the test, 'sticks' at covered - but when tested immediately after a full reboot, the proximity sensor status correctly reflects whether it is covered or not.

On the Xperia XA2 phone, the proximity sensor is in the 'bar' above the lit screen. It also contains the light sensor and the forward-facing camera.

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Just because the symptoms and description is same doesn't mean the problem is same as well. Considering it is almost three years old thread and problem is on a different phone model also makes that highly unlikely.

( 2019-01-17 15:10:36 +0300 )edit

This behaviour happens to my XA2 just the way you described it. I hope that there will be an update rolled out to fix this issue.

( 2019-02-16 08:00:55 +0300 )edit